Combustion device

Abstract

A combustion device is provided with an electromagnetic on-off valve provided in a gas supply path for a burner, and a proportional valve with an adjustment function downstream of the electromagnetic on-off valve, and during ignition, if the opening of the electromagnetic on-off valve is delayed due to the adhesion of a valve body to a valve seat, the valve body can be ignited. When a solenoid of the proportional valve is energized in a state where the air pressure in a primary pressure chamber of the proportional valve is zero, the proportional valve is opened at a maximum opening degree, and it is possible to prevent detonation. When the burner is ignited, first control (STEP3) for opening the electromagnetic on-off valve is performed, and then control (STEP5) for energizing the solenoid of the proportional valve so that the opening degree of the proportional valve reaches a predetermined ignition opening degree is performed.

Description

Technical Field

[0001] The present invention relates to a combustion device including: a burner; an electromagnetic on-off valve provided in a gas supply path to the burner and a proportional valve on the downstream side of the electromagnetic on-off valve; and a control unit. Background Art

[0002] Conventionally, in such a combustion device, the control unit is configured to, when the burner is ignited, simultaneously control the electromagnetic on-off valve to open and energize the solenoid of the proportional valve so that the opening of the proportional valve reaches a specified ignition opening (see, for example, Patent Document 1). In addition, the proportional valve is generally composed of the following proportional valve with an adjustment function, which comprises: a valve housing, which has a primary pressure chamber on the upstream side, a secondary pressure chamber on the downstream side, and a valve seat between the primary pressure chamber and the secondary pressure chamber; a diaphragm, which covers the end surface of the primary pressure chamber on the side opposite to the valve seat; a regulating valve, which has a valve body and a shaft, the valve body is inserted into a valve port formed in the valve seat, and increases the opening of the valve port by shifting from the primary pressure chamber side to the opening side toward the secondary pressure chamber side, the shaft extending from the valve body and connected to the diaphragm; and a solenoid, which is arranged on the opposite side of the primary pressure chamber with the diaphragm separated, the proportional valve is configured so that a pressing force toward the opening side proportional to the current flowing through the solenoid acts on the regulating valve, and the pressure change in the secondary pressure chamber is suppressed by shifting the regulating valve with the help of the diaphragm according to the pressure change in the primary pressure chamber (for example, refer to patent document 2).

[0003] However, when the combustion device is not used for a long time, the valve body of the electromagnetic on-off valve may sometimes stick to the valve seat. In this case, even if the electromagnetic on-off valve is controlled to open during ignition, it takes time until the valve body is peeled off from the valve seat and the electromagnetic on-off valve is opened. Moreover, if the solenoid of the proportional valve is energized in the above manner while the electromagnetic on-off valve is controlled to open, the following undesirable situation will occur. That is, until the electromagnetic on-off valve is opened, the air pressure in the primary pressure chamber of the proportional valve becomes zero (atmospheric pressure), and the pressing force toward the closing side based on the air pressure in the primary pressure chamber of the regulating valve by means of the diaphragm also becomes zero. Therefore, the proportional valve is opened to the maximum opening beyond the ignition opening due to the energization of the solenoid. As a result, when the electromagnetic on-off valve is opened with a delay, excessive gas is temporarily supplied to the burner, which may cause explosion.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-270948

[0007] Patent Document 2: Japanese Patent Application Publication No. 2017-26026 Summary of the invention

[0008] In view of the above problems, an object of the present invention is to provide a combustion device that does not cause explosion even if the opening of the electromagnetic on-off valve is delayed due to the sticking of the valve body to the valve seat during ignition.

[0009] In order to solve the above-mentioned problems, the present invention relates to a combustion device, comprising: a burner; an electromagnetic on-off valve provided in a gas supply path for the burner and a proportional valve on the downstream side of the electromagnetic on-off valve; and a control unit, wherein the proportional valve is composed of a proportional valve with an adjustment function and comprises: a valve housing having a primary pressure chamber on the upstream side, a secondary pressure chamber on the downstream side, and a valve seat between the primary pressure chamber and the secondary pressure chamber; a diaphragm covering the end face of the primary pressure chamber on the side opposite to the valve seat; a regulating valve having a valve body portion and a shaft portion, wherein the valve body portion is inserted into a valve port formed in the valve seat and is adjusted from the primary pressure chamber side toward the secondary pressure chamber side. The opening side of the chamber side is shifted to increase the opening of the valve mouth, and the shaft portion extends from the valve body and is connected to the diaphragm; and a solenoid is arranged on the opposite side of the primary pressure chamber with the diaphragm, so that a pressing force toward the opening side proportional to the current flowing through the solenoid acts on the regulating valve, and the regulating valve is shifted with the help of the diaphragm according to the air pressure change in the primary pressure chamber to suppress the air pressure change in the secondary pressure chamber. It is characterized in that the control unit is constructed as follows: when the burner is ignited, the electromagnetic on-off valve is first controlled to open, and then the solenoid of the proportional valve is energized to make the opening of the proportional valve reach the specified ignition opening.

[0010] According to the present invention, at the time of ignition, the electromagnetic on-off valve is first controlled to open, so that even if the electromagnetic on-off valve is delayed in opening due to the sticking of the valve body to the valve seat, the solenoid of the proportional valve is energized in a state where the gas pressure in the primary pressure chamber of the proportional valve is increased to the primary pressure due to the opening of the electromagnetic on-off valve. As a result, the opening of the proportional valve reaches the ignition opening by controlling the energization of the solenoid, thereby preventing the burner from being over-supplied with gas and causing explosion.

[0011] In addition, in the present invention, preferably, a predetermined waiting time is set according to the time required for the electromagnetic on-off valve to be opened after the control of opening the electromagnetic on-off valve is started in a state where the valve body of the electromagnetic on-off valve is adhered to the valve seat until the valve body is peeled off from the valve seat and the electromagnetic on-off valve is opened, and the control unit is configured to control the solenoid of the proportional valve to be energized after the waiting time has passed after the control of opening the electromagnetic on-off valve is started when the burner is ignited. Accordingly, the time spent after the valve opening control of the electromagnetic on-off valve is started until the solenoid of the proportional valve is energized can be set to the minimum time required to prevent explosion, which is more reasonable.

[0012] In addition, in the present invention, the control unit can be configured such that when igniting the burner, after performing the control to open the electromagnetic on-off valve, the control to close the electromagnetic on-off valve is performed, and then the control to open the electromagnetic on-off valve again is performed, and at the same time, the solenoid of the proportional valve is energized. Here, even if the valve body of the electromagnetic on-off valve adheres to the valve seat, the adhesion of the valve body to the valve seat is eliminated in the initial valve opening control of the electromagnetic on-off valve, and the electromagnetic on-off valve is opened while performing the re-valve opening control of the electromagnetic on-off valve. Therefore, even when the solenoid of the proportional valve is energized while performing the re-valve opening control of the electromagnetic on-off valve, the opening degree of the proportional valve reaches the ignition opening degree, thereby preventing deflagration. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic cross-sectional view of a warm air heater of a combustion device as an embodiment of the present invention.

[0014] Figure 2 shows Figure 1 the structure of the control system of the warm air heater.

[0015] Figure 3 is provided in Figure 1 a side sectional view of the proportional valve of the warm air heater.

[0016] Figure 4 shows the ignition control performed by the control unit of the warm air heater provided in Figure 1 a flowchart of the content. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] Referring to Figure 1 , 1 represents the body of a warm air heater of a combustion device as an embodiment of the present invention. A warm air outlet 1a is provided in the lower part of the front surface of the body 1, and an air inlet 1b is provided in the back surface of the body 1.

[0018] In the body 1, there are arranged: a ventilation box 2, which is communicated with the air inlet 1b; and a fan box 4, which is communicated with the lower end of the ventilation box 2 and internally provided with a fan 3. A combustion housing 6 with a burner 5 is arranged in the ventilation box 2. Moreover, air is inhaled from the air inlet 1b into the ventilation box 2 by the operation of the fan 3, the combustion gas from the combustion housing 6 and the air are mixed, and blown out as warm air from the warm air outlet 1a.

[0019] In addition, an air suction port 6a is provided in the lower part of the back surface of the combustion housing 6. Moreover, a part of the air from the air inlet 1b is sucked into the combustion housing 6 from the air suction port 6a by the negative pressure acting on the upper part of the combustion housing 6 through the operation of the fan 3, and supplied to the burner 5 as combustion air.

[0020] Referring toFigure 2 In the gas supply passage 7 for the burner 5, two on-off valves, namely a first electromagnetic on-off valve 81 and a second electromagnetic on-off valve 82, and a proportional valve 9 are sequentially provided from the upstream side. Each of the electromagnetic on-off valves 81 and 82 is opened when energized and closed by the force of a spring when not energized, thereby cutting off the gas supply to the burner 5.

[0021] The proportional valve 9 is constituted by a proportional valve with an adjustment function. Referring to Figure 3 For a specific description, the proportional valve 9 includes: a valve housing 91 having an upstream primary pressure chamber 911 communicating with an inlet port 911a, a downstream secondary pressure chamber 912 communicating with an outlet port 912a, and a valve seat 913 between the primary pressure chamber 911 and the secondary pressure chamber 912; a diaphragm 92 covering the end face of the primary pressure chamber 911 on the side opposite to the valve seat 913; a regulating valve 93 having a valve body portion 931 and a shaft portion 932, the valve body portion 931 being inserted through a valve port 913a formed in the valve seat 913 and increasing the opening degree of the valve port 913a, that is, the opening degree of the proportional valve 9, by shifting from the primary pressure chamber 911 side toward the opening side of the secondary pressure chamber 912 side, the shaft portion 932 extending from the valve body portion 931 and being connected to the diaphragm 92; and a solenoid 94 disposed on the side opposite to the primary pressure chamber 911 with the diaphragm 92 interposed therebetween. A pressing force toward the opening side proportional to the energizing current for the solenoid 94 (precisely, the energizing current for the coil 941 of the solenoid 94) acts on the regulating valve 93 by means of a plunger 942 of the solenoid 94. Therefore, the air pressure in the secondary pressure chamber 912 changes in proportion to the energizing current for the solenoid 94 according to the opening degree of the proportional valve 9, so that the amount of gas supplied to the burner 5 changes. In addition, the regulating valve 93 is displaced by means of the diaphragm 92 according to the air pressure variation in the primary pressure chamber 911, whereby an adjustment function for suppressing the air pressure variation in the secondary pressure chamber 912 can be obtained. Further, in the present embodiment, the primary pressure chamber 911 is located below and the secondary pressure chamber 912 is located above. Moreover, a spring 943 is provided to apply an upward force to the plunger 942 to offset the self-weights of the plunger 942 and the regulating valve 93.

[0022] An ignition electrode 10a, which performs spark discharge due to the energization operation of an igniter 10, and a thermocouple 11, which serves as a flame detection element for monitoring the flame of the burner 5, are additionally provided on the burner 5. In addition, a room temperature sensor 12 facing the air inlet 1b and a controller 13 as a control unit are provided in the body 1. The controller 13 controls a fan motor 3a for driving the fan 3, the two on-off valves, namely the first and second electromagnetic on-off valves 81 and 82, the proportional valve 9, and the igniter 10. Further, signals from switches such as an operation switch on an operation panel 1c provided on the upper surface of the body 1, and output signals from the thermocouple 11 and the room temperature sensor 12 are input to the controller 13.

[0023] When the operation switch is turned on, the controller 13 first performs ignition control, and the following operations are carried out in this ignition control: rotating the fan 3, energizing the igniter 10, opening the two on-off valves, i.e., the first and second electromagnetic on-off valves 81 and 82, and setting the opening degree of the proportional valve 9 to a prescribed ignition opening degree. In addition, the following temperature adjustment control is carried out: after the burner 5 is ignited by the ignition control, the supply gas amount to the burner 5 is increased or decreased by the proportional valve 9 according to the deviation between the heating set temperature and the room temperature detected by the room temperature sensor 12, and the rotational speed of the fan 3 is increased or decreased according to the supply gas amount.

[0024] Here, if the opening of either of the first and second electromagnetic on-off valves 81 and 82 lags due to the adhesion of the valve body to the valve seat, and the solenoid 94 of the proportional valve 9 is energized before the electromagnetic on-off valve is opened, then in a state where the pressing force toward the closing side based on the air pressure in the primary pressure chamber 911 acting on the regulating valve 93 via the diaphragm 92 is zero, the pressing force toward the opening side based on the energization of the solenoid 94 acts on the regulating valve 93, causing the proportional valve 9 to open to the maximum opening degree exceeding the ignition opening degree. As a result, when the electromagnetic on-off valve lags in opening, an excessive amount of gas is temporarily supplied to the burner 5, which may cause deflagration.

[0025] Therefore, in the present embodiment, the controller 13 performs Figure 4 the ignition control shown. Regarding this ignition control, first, in STEP1, the control to rotate the fan 3 is started, and in STEP2, the energization of the igniter 10 is started, and in STEP3, the control to open the two on-off valves, i.e., the first and second electromagnetic on-off valves 81 and 82, is started. Specifically, the control to energize the two electromagnetic on-off valves 81 and 82 is started. Next, in STEP4, it is determined whether a prescribed waiting time has elapsed after the start of the opening control of the two electromagnetic on-off valves 81 and 82. This waiting time is set, for example, to 0.7 seconds corresponding to the time required until the valve body of the first and second electromagnetic on-off valves 81 and 82 is peeled off from the valve seat and the electromagnetic on-off valves 81 and 82 are opened after the start of the opening control of the electromagnetic on-off valves 81 and 82 in a state where the valve body is adhered to the valve seat. And when the waiting time has elapsed, it proceeds to STEP5, and the control to energize the solenoid 94 of the proportional valve 9 is carried out so that the opening degree of the proportional valve 9 reaches the prescribed ignition opening degree. In addition, the above-mentioned time required until the electromagnetic on-off valves 81 and 82 are opened is studied in advance through experiments and the like.

[0026] According to the above control, even if the opening of either of the first and second electromagnetic on-off valves 81 and 82 is delayed due to the adhesion of the valve body to the valve seat, the solenoid 94 of the proportional valve 9 is energized in a state where the air pressure in the primary pressure chamber 911 of the proportional valve 9 has risen to the primary pressure (the supply air pressure to the gas supply passage 7) due to the opening of the two electromagnetic on-off valves 81 and 82. As a result, the opening degree of the proportional valve 9 is changed to the ignition opening degree by the energization control of the solenoid 94, and it is possible to prevent an excessive amount of gas from being supplied to the burner 5 and causing deflagration.

[0027] If the energization control of the solenoid 94 of the proportional valve 9 is started as described above, then in STEP6, it is determined based on the signal from the thermocouple 11 whether ignition of the burner 5 is monitored. Moreover, when ignition is monitored, in STEP7, the energization of the igniter 10 is stopped, a series of processes are ended, and temperature adjustment control is entered. When ignition is not confirmed, in STEP8, it is determined whether a predetermined time (for example, 10 seconds) has elapsed after the start of the energization control of the solenoid 94 of the proportional valve 9. Moreover, when the predetermined time has elapsed in a state where ignition is not confirmed, it is determined that an ignition failure has occurred and the process proceeds to STEP9, and the following operations are performed: the energization of the igniter 10 is stopped, the first and second electromagnetic on-off valves 81 and 82 are closed, the energization of the solenoid 94 of the proportional valve 9 is stopped, the fan 3 is stopped, and in STEP10, an ignition failure is reported and the ignition control is aborted.

[0028] However, it is also considered to set the waiting time for the determination in STEP4 to be longer than the above time. However, if the waiting time is set to the above time, the time taken from the start of the opening control of the first and second electromagnetic on-off valves 81 and 82 until the energization of the solenoid 94 of the proportional valve 9 can be set to the minimum time required to prevent deflagration, which is more reasonable. In addition, it can be considered that the degree of adhesion of the valve body of the electromagnetic on-off valves 81 and 82 to the valve seat varies depending on the length of the non-use period of the warm air heater. Therefore, the non-use period can be detected, and the waiting time can be variably set according to the length of the non-use period in such a way that the shorter the non-use period, the shorter the waiting time.

[0029] The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited thereto. For example, in the above embodiments, after a waiting time has elapsed since the start of the opening control of the electromagnetic on-off valves 81 and 82, the energization control of the solenoid 94 of the proportional valve 9 is started. However, after a waiting time has elapsed since the start of the opening control of the electromagnetic on-off valves 81 and 82, control to close the electromagnetic on-off valves 81 and 82 may be performed, and then control to open the electromagnetic on-off valves 81 and 82 again may be performed. At the same time, the energization control of the solenoid 94 of the proportional valve 9 is started. Here, even if the valve bodies of the electromagnetic on-off valves 81 and 82 are adhered to the valve seats, the adhesion of the valve bodies to the valve seats is eliminated in the first opening control of the electromagnetic on-off valves 81 and 82, and the electromagnetic on-off valves 81 and 82 are opened at the same time as the second opening control of the electromagnetic on-off valves 81 and 82. Therefore, even if the solenoid 94 of the proportional valve 9 is energized at the same time as the second opening control of the electromagnetic on-off valves 81 and 82, the opening degree of the proportional valve 9 becomes the ignition opening degree, and thus knocking can be prevented. In this case, a time difference may be set to perform the first opening control of the first electromagnetic on-off valve 81 and the second electromagnetic on-off valve 82.

[0030] In addition, in the above embodiments, the primary pressure chamber 911 of the proportional valve 9 is located below the secondary pressure chamber 912, but the primary pressure chamber 911 may be located above the secondary pressure chamber 912. And, in the above embodiments, in order to improve the reliability of preventing gas leakage during non-use, two on-off valves, the first and second electromagnetic on-off valves 81 and 82, are provided, but the number of electromagnetic on-off valves may be set to one. In addition, the above embodiments apply the present invention to a warm air heater, but the present invention may equally be applied to combustion devices other than warm air heaters.

[0031] Description of Reference Numerals

[0032] 5... Burner; 7... Gas supply passage; 81, 82... Electromagnetic on-off valves; 9... Proportional valve; 91... Valve housing; 911... Primary pressure chamber; 912... Secondary pressure chamber; 913... Valve seat; 913a... Valve port; 92... Diaphragm; 93... Regulating valve; 931... Valve body portion; 932... Shaft portion; 94... Solenoid; 10... Controller (control unit).

Claims

1. A combustion device includes: a burner; an electromagnetic on-off valve provided in a gas supply path for the burner and a proportional valve on the downstream side of the electromagnetic on-off valve; and a control unit. The proportional valve is constituted by a proportional valve with an adjustment function and includes: a valve housing having a primary pressure chamber on the upstream side, a secondary pressure chamber on the downstream side, and a valve seat between the primary pressure chamber and the secondary pressure chamber; a diaphragm covering the end face of the primary pressure chamber on the side opposite to the valve seat; a regulating valve having a valve body portion and a shaft portion, the valve body portion being inserted through a valve port formed in the valve seat and increasing the opening degree of the valve port by shifting from the primary pressure chamber side toward the opening side toward the secondary pressure chamber side, the shaft portion extending from the valve body portion and being connected to the diaphragm; and a solenoid disposed on the side opposite to the primary pressure chamber with the diaphragm interposed therebetween. A pressing force toward the opening side proportional to the energizing current for the solenoid acts on the regulating valve, and the regulating valve is displaced by the diaphragm according to the air pressure change in the primary pressure chamber to suppress the air pressure change in the secondary pressure chamber. It is characterized in that The control unit is configured to: when igniting the burner, first perform control to open the electromagnetic on-off valve, and then perform control to energize the solenoid of the proportional valve so that the opening degree of the proportional valve reaches a specified ignition opening degree.

2. The combustion device according to claim 1, characterized in that A specified waiting time is set corresponding to the time required from the start of the control to open the electromagnetic on-off valve until the valve body is peeled off from the valve seat and the electromagnetic on-off valve is opened in a state where the valve body of the electromagnetic on-off valve is adhered to the valve seat. The control unit is configured to: when igniting the burner, perform control to energize the solenoid of the proportional valve when the waiting time has elapsed after the start of the control to open the electromagnetic on-off valve.

3. The combustion device according to claim 1, characterized in that The control unit is configured to: when igniting the burner, after performing control to open the electromagnetic on-off valve, perform control to close the electromagnetic on-off valve, and then perform control to open the electromagnetic on-off valve again, and at the same time perform control to energize the solenoid of the proportional valve.

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